This invention relates to an improvement on rimless spectacles, in more details, pertaining to the rimless spectacles with lens holding stability whose lenses are very stably jointed to its engagement parts without the displacement thereof during use and whose stability in shape lasts for a long period of time.
Because the rimless spectacles is light in weight, wide in field of vision and comfortable to wear on, and is also shapely in design, the number of the wearers to use such spectacles recently increases. As known, the rimless spectacles comprise a front frame formed by interconnecting a pair of right-and-left lenses through a bridge and a temple that is engaged to the respective ends of said front frame through an endpiece. However, a clamping hole is bored at a portion of the respective lenses, to which portion the bridge and the endpiece are engaged, and the respective lenses have to be clamped with a screw at such hole through a strap provided on the bridge and the endpiece.
However hard the respective lenses are clamped with a screw, the spectacles are subjected to incessant vibrations and external forces during use so that the engagement portion between the bridge or endpiece and the respective lenses becomes easy to fluctuate, which further brings the whole front frame into fluctuation. Then, as a countermeasure against such problem, such measure has been taken as fusing a splint plate having a shape corresponding to the side fringe of the respective lenses on a counterpart portion of the bridge and the endpiece respectively and abutting this splint plate onto the side fringe thereof so as to prevent the relative movement between the bridge or the endpiece and the respective lenses.
However, the provision of such splint plate on the bridge and the endpiece has no effect to stop the fluctuation of the screw clamping portions, and the splint plate comes to slide along the side fringe of the respective lenses centering on the clamping portion (or clamping hole) of the respective lenses because of the smoothness of the side fringe surface, which results in being unable to prevent the displacement of the clamping position of the respective lenses. It occurs in the case of prescription eyeglasses that the displacement of the clamping position of the respective lenses invites the misalignment between the pupil distance of a wearer and the optical axis of the right-and-left lenses so as to cause eyestrains to the wearer.
In view of the above inconveniences encountered with the prior art and in order to solve such prior issues as mentioned above, the present invention is to provide the rimless spectacles with lens holding stability whose right-and-left lenses are very stably jointed to its engagement parts so as to be held in proper position against minute vibrations or incessant external forces and whose stability in shape lasts for a long period of time.
The present invention is further to provide the rimless spectacles whose assembly parts are small in number and whose design is shapely, and also which can be more far efficiently assembled than the rimless spectacles with the conventional assembly.
The present invention is further to provide the rimless spectacles whose assembly parts are simple in shape so as to be advantageous for the parts inventory control and the maintenance thereof.
The means adopted in the invention to solve the above issues are described below with reference to the accompanying drawings.
That is to say, the rimless spectacles according to the present invention is characterized in comprising a bridge 2 that is a metallic member to form a front frame F by holding a pair of lenses 1 and 1 in juxtaposition, said bridge being provided with a stay bar 21 to keep the respective lenses at a certain interval and a splint plate 22 provided at the respective ends of said stay bar 21 to abut onto a fringe side of the respective lenses 1 and 1 and a pin 23 to poke through and support for connection the respective lenses 1 and 1 in a vicinity of the splint plate 22; an endpiece 3 that is a metallic member extensively engaged to an outer end portion of the respective lenses 1 and 1 of the front frame F, said endpiece being provided with a splint plate 31 to abut onto an outer side fringe of the respective lenses 1 and 1 and a pin 32 to poke through and support for connection the respective lenses 1 and 1 in a vicinity of the splint plate 31; a pressure exerting screw 4 that is screwed in the splint plate 31 of the respective endpieces 3 and the respective splint plates 22 of the bridge 2 to prevent fluctuation of said plates, said screw 4 being driven through the respective splint plates with said plates abutted onto the side fringe of the respective lenses 1 and 1 so as to set in said fringe side through an end portion 41 thereof and a temple 5 that is extended with regard to a backside of the front frame F through the respective endpieces 3 and 3.
As for the materials of the assembly parts of the rimless spectacles according to the present invention, an inorganic glass may be adopted for the lenses 1 and 1 to be used in this invention, but those conventionally well-known plastic lenses molded from such as methacrylic resin, polystyrene resin, styrene-acrylic resin, polyurethane resin and polycarbonate resin are also available, provided that light weight is of most concern. Some of the examples of the lenses 1 and 1 to be used for the rimless spectacles of the present invention include such prescription lenses as a concave lens for nearsightedness, a convex lens for farsightedness, a cylinder lens for astigmatism, a bi-focal lens and a progressive focal lens or such protection lens for the retinas as blocking UV and IR rays or such polarized lens as preventing dizziness. The respective lenses 1 and 1 to form the front frame F are provided with the respective clamping holes 11 and 11, into which the pins 23 and 32 are inserted, to the side of the bridge 2 and the endpiece 3.
Then, the examples of the materials for the bridge 2 and the endpiece 3 include such alloys as German silver, Monel, Stainless and Nickel-Chromium compounds that are used for a pair of spectacles, the lenses of which are enclosed with a metallic rim. Instead of such alloys, the rare metal such as 18 k. Gold is also adoptable. Provided that being light in weight is of most concern, preferably, aluminous alloy, xcex2-titanium or magnesium alloy is adoptable while a super elastic alloy such as nickel-titanium alloy is adoptable for improving the comfortableness to wear the spectacles on. In the above cases, the pin 23 of the bridge 2 and that 32 of the endpiece 3 respectively may be integrally molded with themselves by means of lost wax process and so forth, but those pins maybe separately attached onto themselves by means of either welding process or brazing process. This also applies to the pad arms as described below, into which arm a nose pad is mounted.
Then, the temple 5 may be made from metallic material or synthetic resin. Where it is made from the latter, it should be hinged to the extensive portion 33 of the endpiece 3 so that it is required to be provided at its proximal end portion with a metallic hinge lobe 51. On the other hand, where it is made from metallic material, it does not necessarily require such hinge mechanical parts. However, it is required to provide a portion 52 that is easy to bend and good at flexibility with its proximal end portion, which portion may be arranged to thin, for instance. Where a metallic temple 5 is hinged onto the extensive portion 33 of the endpiece 3, it is understood that the hinge lobe 51 is integrally provided at the proximal end portion of the temple or fixed to the same end portion by welding process or brazing process.
In addition to the above means, the present invention provides further purpose-minded rimless spectacles together with the following concrete means.
(a) Provided that the pin 23 of the bridge 2 and that 32 of the endpiece 3 are made from metallic material so as to make those pins rigid, when the pressure exerting screw 4 is screwed in the splint plates 22 and 31 of the bridge 2 and the endpiece 3 respectively so as to pressurize the side fringes of the respective lenses 1 and 1, the respective lenses are firmly interposed between the pins 23 and 32 and the corresponding splint plates 22 and 31 respectively so as to be stably held in check without displacement or fluctuation.
(b) Provided that the pin 23 of the bridge 2 and that 32 of the endpiece 3 are made from super elastic alloy, it allows the force to clamp the respective lenses between the pin and the splint plate to be optimized and made flexible. The conventionally known welding or brazing process may be adopted for the jointing of the pin 23 to the bridge 2 and the pin 32 to the endpiece 3, which pins are made from super elastic alloy.
(c) Provided that the respective lenses 1 and 1 to form a front frame F are made from synthetic resin, the sharpening of the end portion 41 of the pressure exerting screw 4, which portion contacts the side fringes of the respective lenses 1 and 1, allows said end portion 41 to seize the side fringes thereof with a pointed end when the screws 4 are driven into the splint plates, so as to prevent those plates from fluctuating with regard to the fringe sides of the respective lenses.
(d) Provided that the respective lenses 1 and 1 to form a front frame F are made from glass, it is preferred to use a pressure exerting screw that is made from such super hard alloy as WCxe2x80x94TiCxe2x80x94Co based alloy or WCxe2x80x94TiCxe2x80x94TaCxe2x80x94Co based alloy that is hard enough to make a scratch on the surface of the lens.
(e) The rough or knurling finishing to be performed at least on a portion of the side fringes of the respective lenses 1 and 1, onto which portion the end portion 41 of the pressure exerting screw 4 abuts, allows the effect brought by the screw to prevent the lens from fluctuating to further improve.
(f) The temple 5 may be arranged such that it is collapsibly hinged to the hinge lobes 34 provided at the extensive portion 33 of the endpiece 3, but the endpiece 3 and the temple 5 may be integrally formed in one streak instead of such hinge arrangement. In the latter case, a portion 52 easy to bend is provided with the temple 5 in the vicinity of the front frame F, which portion 52 allows the temple to collpase.
(g) A pad arm 24 to be provided at the respective ends of the bridge 2 allows a nose pad P to be mounted into the end portion of the said pad arm 24.